Luminaire



T. W. ROLPH Jan. 9, 1940.

LUMINAIRE 2 Sheets-Sheet 1 Filed Oct. 25, 1937 INVENTOR THOMAS W. ROLPH ATTORNEY T. W. ROLPH Jan; 9,' 1940.

LUMINAIRE Filed 001;. 23, 1957 2 Sheets-Sheet 2 INVENTOR Thomas W Ralph ATTORNEY Patented Jan 9, 1940 1 UNITED STATES Z,l86,079 v 2,180,019 LUMINAIRE L Thomas W. Rolph, Newark,

Holophane Company, Inc., corporation of Delaware Ohio, assignor to New York, N. Y.', a

Application October 23, 1937, Serial No. 170,564 '1. Claims. (Cl. 240-25) The present invention relates to luminaires, and is more particularly directed toward luminaires designed for lighting extended areas such as street surfaces.

The present invention contemplates the use of a long light source normally mounted horizontal and a combination of prisms and reflectors designed to act on the light to direct it toward the remote street areas.

A further object of the invention is to provide an arrangement of light controlling elements particularly suitable for use with sodium tube lighting.

The accompanying drawings show, for purposes of illustrating the present invention two of the many embodiments in which the invention may take form, drawings are illustrative of the invention rather than limiting the same.

In these drawings:

Figure 1 is a vertical sectional view through a street lighting luminaire with parts in elevation;

Figure 2 is a typical cross sectional view on the.

line 2-2 of Figure 1; Figure 3 is an enlarged fragmentary view; and Figure 4 is a view similar to Figure 1 showing a modification.

The evacuated bulb of a sodium lamp is indicated at Hi. It is surrounded by the usual heat conserving enclosure II. An ordinary long lamp bulb of the incandescent type may be used if desired. 7

The light source is surrounded by a prismatic envelope preferably made in two parts l2 and I3. These parts are held together by a metal band l4 spun about the flanges IS. The parts l2 and I3 may be readily made of pressed glass. The inside walls of these prismatic parts I2 and I3 are provided with longitudinally extending ribs which form prisms for light control.

In the region from zenith down approximately to, but preferably slightly below, the horizontal the prisms are arranged to concentrate light rays, such as I6, into an obliquely upwardly directed beam of parallel light rays H. In the region from slightly below the horizontal to a considerable distance above the horizontal the prisms are such as to act on divergent light rays l8 and concentrate them into a downwardly sloping beam of parallel rays, indicated at l9. In the region below the point marked D these prismatic forms overlap, and the prisms are formed by ribbings such as indicated in Figure 3. One face of a rib acts onthe rays iii to elevate them, while the other face of the rib acts on the rays it being understood that the N to depress them. At the lower part of the prism area practically all of the light is refracted into the downward beam, and as the prism formation extends upwardly less and less of the light is rei'ractedinto the downward beam and more and more of the light is refracted into the upward beam. Toward the upper part of the prismatic area all of the light is refracted into the upward beam. This prismatic formation achieves a high efficiency in the use of the light. 19

The prismaticenvelope and light source are mounted in any suitable manner below a V- shaped reflector 20, 20. This is preferably a metal reflector. Each side of the V-shaped reflector is placed at an oblique angle with respect 15 to the light rays l1 and acts onthese light rays to direct them downwardly and outwardly, as indicated at 2|. According to the preferred design the rays 2| and I! are parallel. Owing to the size of the light source of the sodium lamp 20 there would be considerable spread of the light rays above and below the lines indicated in the drawings.

The enclosure l2, l3 affords an added heat conserving medium, so as to protect the enclosed 25 light source against weather and against loss of heat.

In the arrangement shown in Figure 4, the same ultimate result is achieved by employing a refractor 4| having prisms 42 which concentrate so the light into a moderately divergent beam 43 having a virtual center at 44. These rays fall on a parabolic reflector 46 and are directed into a beam of parallel rays 41. The lower prisms may be the same as those of Figure 1 so far as 35 producing a downwardly directed beam 48 is concerned.

It is obvious that the invention may be embodied in many forms and constructions within the scope of the claims and I wish it to be under- 40 stood that the particular forms shown are but two of the many forms. Various modifications and changes being possible, I do not otherwise limit myself in any way with respect thereto.

What is claimed is:

1.. A luminaire comprising a horizontal rectilinear light source, a refractor concave toward the light source and having a series of prisms extending parallel with the light source, which retract rays in a predetermined zone from zenith 50 into a beam directed obliquely above the horizontal, a rectilinear reflector parallel with and above the source and disposed obliquely to said refracted beam to intercept the same and reflect its rays into a downwardly oblique beam of sub- 64 from the source and retracting it into a beam substantially parallel with the beam reflected from the reflector. I

.2. A luminaire' such as claimed in claim 1,

wherein throughout a portion of the region occupied thereby the active surfaces of the prisms of one series alternate with the active suriaces of the prisms of the other series so that the bundles of rays falling on two adjacent surfaces are divided and one bundle deviated into the upper beam and the other bundle deviated into the lower beam.

3. A luminaire such as claimed in claim 1, wherein the reflector is in a plane and the flrst mentioned series of prisms are such that the upwardly extending beam is composed of parallel ys. A a

4. A luminaire such as claimed in claim 1, wherein the reflector is of parabolic cross section with its focus below and at the opposite side of the light source, and the flrst mentioned series of prisms are such that the upwardly extending beam is composed oi rays diverging from said focus.-

5, In a luminaire, a light source, a concentric prismatic member having prisms acting on light from the light source for concentrating rays into a beam directed above the horizontal, a reflector intercepting the reflected rays obliquely and reflecting them into a substantially parallel beam, the concentrating prisms opposite the more remote portion 0! the reflector alternating with light concentrating prisms 0t reversed sign which divert the rays intercepted thereby into a direct beam substantially parallel with the reflected beam.

' 6. In a iuminaire, a light source, a. concentric prismatic member having prisms acting on. light irom the light source for concentrating rays into a beam directed above the horizontal, a reflector intercepting the reflected rays obliquely and reflecting them into a substantially parallel beam, the concentrating prisms opposite the more remote portion of the reflector alternating with light concentrating prisms 0t reversed sign which shaped reflector, a rectilinear light source disposed below the center 0! the reflector, and a refractor about the source, the reiractor having two sets of longitudinally extending prisms each adapted to produce a beam of rays which falls on the adjacent side 01' the reflector, the angle of the v being such that the reflected beams are directed outwardly below the horizontal, the refractor also having two sets of longitudinally extending prisms each acting on direct light and concentrating it into a beam generally parallel with and below the adjacent reflected beam.

\ THOMAS W. ROLPH. 

